Entity self-clustering and host-entity communication as via shared memory

ABSTRACT

The self-clustering of entities within a system is disclosed. The system can also include a host. Each entity self-discovers all the other entities, such that the entities are aggregated as a cluster. The host communicates with the cluster of entities, where the entities are self-clustered or otherwise, such as through a memory shared by all the entities. The host therefore need not be aware which of the entities performs a given function.

BACKGROUND OF THE INVENTION

[0001] 1. Technical Field

[0002] This invention relates generally to entities, such as serviceprocessors that may be found within nodes of a system, and moreparticularly to the self-clustering of such entities, so that, forinstance, a single image of the service processors appears to theoperating system of the system and/or a management console for thesystem.

[0003] 2. Description of the Prior Art

[0004] As computer systems, such as server systems, become more complex,they have been divided into different nodes that operate as separateunits. Each node may have its own processors, memory, and input/output(I/O) modules. Functionality performed by a system may be divided amongits various nodes, such that each node is responsible for one or moredifferent functions. Each node has a service processor (SP) thatfunctions independently of the service processors of the other nodes,but which allows external access to the hardware of its node.

[0005] A complication to dividing a system into different nodes is thatthe operating system (OS) running collectively on the system, and themanagement consoles used to manage the system externally, havetraditionally had to be aware of the specific aspects of this divisioninto nodes. The operating system, for instance, has to know whichservice processor is responsible for which hardware and functionality ofthe system, so that messages can be routed to the appropriate serviceprocessor. Similarly, management consoles have to know the mapping ofthe service processors to the system's hardware and functionality.

[0006] This adds increased complexity to the operating system and themanagement consoles. Significant configuration may have to beaccomplished to ensure that the operating system and the consoles areproperly aware of the different service processors and the functionsthat have been assigned to them. Furthermore, like all systemcomponents, service processors sometimes fail. To ensure that the systemitself does not fail, another service processor may have to temporarilyact as the failover processor for the down processor. The operatingsystem and the consoles must be aware of such failover procedures, too.Load balancing and other inter-service processor procedures also requireknowledge of the distribution of functionality over the serviceprocessors.

[0007] In addition, traditional communication between an operatingsystem and the service processors of the system occurs within thefirmware of the system. Firmware is software that is stored in hardware,such that the software is retained even after no power is applied to thehardware. The use of conventional firmware, however, degradesperformance significantly. For instance, firmware is not re-entrant.That is, only one processor can execute the firmware at a single time.This means that the firmware may present a bottleneck to the efficientrunning of the system.

[0008] In other contexts, the management of multiple resources isaccomplished on a simplistic basis. For example, in the context ofstorage devices, such as hard disk drives, a redundant array ofinformation disks (RAID) provides for limited interaction amongresources. A RAID may be configured so that each hard drive redundantlystores the same information, that data is striped across the hard drivesof the array for increased storage and performance, or for additional orother purposes. However, the drives themselves do not activelyparticipate in their aggregation. Rather, a master controller isresponsible for managing the drives, such that the drives themselves arenot aware of one another.

[0009] Therefore, such solutions are not particularly apt in the systemdivision of functionality and hardware over multiple service processorsscenario that has been described. For example, having a mastercontroller in this scenario just shifts the burden of knowing thefunctionality and hardware division from the management consoles and theoperating systems to the controller. This does not reduce complexity,and likely does not prevent reductions in system performance.

[0010] Other seemingly analogous resource management approaches havesimilar pitfalls. Network adapters that can be aggregated to providegreater bandwidth, for instance, are typically aggregated not amongthemselves, but by a host operating system and/or device driver. Thishost operating system and/or device driver thus still takes on thecomplex management duties that result when multiple resources aremanaged as a single resource. In other words, complexity is still notreduced, and potential performance degradation is still not prevented.

[0011] For these described reasons, as well as other reasons, there is aneed for the present invention.

SUMMARY OF THE INVENTION

[0012] The invention relates to entities, such as service processors,within a system. In a method of the invention, each entityself-discovers all the other entities, such that the entities areaggregated as a cluster. Each entity maintains an object map thatrepresents the hardware of the system for which it is responsible asobjects. A first identifier and a second identifier uniquely identifyeach object. The first identifier corresponds to the entity on which theobject resides, whereas the second identifier distinguishes the objectfrom other objects also residing on the entity.

[0013] A system of the invention includes a self-aggregated cluster ofentities, and a host. The host communicates with the cluster of entitiessuch that it need not be aware which of the entities performs a givenfunction. An article of manufacture of the invention includes acomputer-readable medium and means in the medium. The means is for anentity of a system self-discovering all the other entities of the systemto aggregate the entities as a cluster. The means is further for theentity maintaining an object map representing the resources of thesystem for which it is responsible as objects.

[0014] Other features and advantages of the invention will becomeapparent from the following detailed description of the presentlypreferred embodiment of the invention, taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a diagram of a system according to a preferredembodiment of the invention, and is suggested for printing on the firstpage of the issued patent.

[0016]FIG. 2 is a diagram of a system including a number of serviceprocessors communicating with one another over a service processornetwork, in conjunction with which embodiments of the invention can beimplemented.

[0017]FIG. 3 is a diagram of the system of FIG. 2 with the addition of amanagement console, in conjunction with which embodiments of theinvention can be implemented.

[0018]FIG. 4 is a diagram of the system of FIG. 2 with the addition ofshared memory and an operating system, in conjunction with whichembodiments of the invention can be implemented.

[0019]FIG. 5 is a flowchart of a method showing how service processorscan self-cluster with one another, according to an embodiment of theinvention.

[0020]FIG. 6 is a diagram showing first and second identifiers of anexample node.

[0021]FIG. 7 is a diagram showing an example object map in which firstand second identifiers are stored.

[0022]FIG. 8 is a flowchart of a method showing how an operating systemcan communicate with self-clustered service processors, according to anembodiment of the invention.

[0023]FIG. 9 is a diagram showing an example system in which a memoryshared by a number of service processors has been divided into differentparts, or channels, where each service processor is responsible for asubset of these channels.

[0024]FIG. 10 is a flowchart of a method showing how a managementconsole can communicate with self-clustered service processors,according to an embodiment of the invention.

[0025]FIG. 11 is a diagram of a system according to a more generalembodiment of the invention in which a host communicates withself-clustered entities through a shared memory.

DESCRIPTION OF THE PREFERRED EMBODIMENT Overview

[0026] In the preferred embodiment of the invention, a number of serviceprocessors are self-aggregated together in a single cluster. FIG. 1shows a system 100 in which the service processors 102 a, 102 b, . . . ,102 n have been self-aggregated together in a single cluster, orcomplex, 102. The service processors 102 a, 102 b, . . . , 102 n may bethe processors of the computing nodes of the system 100 (notspecifically shown in FIG. 1), in which each computing node includesvarying hardware of the system 100. The service processors 102 a, 102 b,. . . , 102 n are self-clustered in that no controller, host, or otherentity is responsible for their clustering. Rather, the serviceprocessors 102 a, 102 b, . . . , 102 n discover themselves on their ownto form the cluster 102.

[0027] The service processors 102 a, 102 b, . . . , 102 n appear as asingle cluster 102 to an operating system (OS) 106 and a managementconsole 108. For instance, with respect to the OS 106, the cluster 102communicates with the OS 106 through a shared memory 104. The memory 104is shared by all the processors 102 a, 102 b, . . . , 102 n within thecluster 102. Communication between the cluster 102 and the OS 106 issuch that the OS 106 is preferably unaware which of the processors 102a, 102 b, . . . , 102 n performs a given function. For example, the OS106 may place a message in a part of the memory 104 allocated for acertain function, such that the one of the processors 102 a, 102 b, . .. , 102 n responsible for this function monitors this part of the memory104 and processes the message.

[0028] With respect to the console 108, the console 108 preferablycommunicates through any one of the service processors 102 a, 102 b, . .. , 102 n of the cluster 102. As shown in FIG. 1, this is the serviceprocessor 102 b. The service processor 102 b determines whether amessage received from the console 108 is intended for one of the otherservice processors of the cluster 102, or for itself, and routes themessage accordingly. The console 108 is thus preferably unaware that theservice processors 102 a, 102 b, . . . , 102 n have been clustered asthe cluster 102 to perform functionality for the console 108. Allcommunication between the console 108 and the cluster 102 is preferablyhandled through the service processor 102 b.

Technical Background

[0029]FIG. 2 shows a system 200 of a number of computing nodes 202 a,202 b, . . . , 202 n, containing service processors 102 a, 102 b, . . ., 102 n, that communicate with one another over a service processornetwork 204. The nodes 202 a, 202 b, . . . , 202 n include hardware thatmake up the system 200, and by which the nodes 202 a, 202 b, . . . , 202n perform functionality within the system 200. The service processors102 a, 102 b, . . . , 102 n, and more specifically the firmware thereof,manage the performance of this functionality. Firmware is software thatis stored in hardware, such that the software is retained even after nopower is applied to the hardware. The network 204 may be an Ethernetnetwork, or another type of network. The firmware of the serviceprocessors 102 a, 102 b, . . . , 102 n, of the computing nodes 202 a,202 b, . . . , 202 n, respectively, handles communication to and fromthe network 204.

[0030]FIG. 3 shows a system 300 in which the management console 108communicates with the service processor 102 b of the node 202 b. Theconsole 108 may be, for instance, a desktop computer. The console 108communicates with the service processor 102 b over the network 204.However, the console 108 is only aware of the service processor 102 b.For instance, the console 108 may only know the network address of theservice processor 102 b. Therefore, the console 108 only communicateswith the service processor 102 b, as indicated by the dotted line 302,even though it is communicatively connected to the network 204 overwhich all the service processors 102 a, 102 b, . . . , 102 ncommunicate.

[0031]FIG. 4 shows a system 400 in which the operating system (OS) 106communicates with the service processors 102 a, 102 b, . . . , 102 nthrough the shared memory 104. The shared memory 104 is shown asaccessible to all the nodes 202 a, 202 b, . . . , 202 n, and thus to allthe service processors 102 a, 102 b, . . . , 102 n of these nodes. Theshared memory 104 may be the memory of one or more of the nodes 202 a,202 b, . . . , 202 n. The service processors 102 a, 102 b, . . . , 102 nof the nodes 202 a, 202 b, . . . , 202 n access the shared memory 104through the nodes' memory interconnect.

Self-Clustering of Service Processors

[0032]FIG. 5 shows a method 500 of an embodiment by which serviceprocessors self-aggregate as a single cluster or complex. The method 500can be implemented in conjunction with the systems 100, 200, 300, and400 of FIGS. 1, 2, 3, and 4, respectively. The method 500 can also beimplemented in conjunction with an article of manufacture having acomputer-readable signal-bearing medium. The medium may be a recordabledata storage medium, a modulated carrier signal, or another type ofmedium.

[0033] The service processors first self-discover one another (502),such that the service processors are aggregated as a cluster. Eachservice processor also maintains an object map representing the hardwareof the system for which it is responsible as objects (504). Twoidentifiers uniquely identify each object. The first identifiercorresponds to the service processor on which the object resides. Thesecond identifier distinguishes the object from other objects residingon the same service processor.

[0034]FIG. 6 shows diagrammatically the difference between these twoidentifiers. Within an example node 600, there is a service processor602, and two pieces of hardware, a first hardware 604 and a secondhardware 606. The first identifier 608 identifies the service processor602. The second identifier 610 is associated with the objectrepresenting the first hardware 604, whereas the second identifier 612is associated with the object representing the second hardware 606.Thus, the combination of the first identifier 608 and either the secondidentifier 610 or the second identifier 612 uniquely identifies theservice processor 602 and a specific object instance uniquelyidentifying either the hardware 604 or 606. For example, the combinationof the first identifier 608 and the second identifier 610 uniquelyidentifies the service processor 602 as storing the object specificallyrepresenting the hardware 604.

[0035] The first identifier 608 may be any identifier unique to theservice processor 602, such as the service processor's serial number orits Ethernet address. Other unique identifiers include combinations ofone or more of the media access controller (MAC) address of the serviceprocessor 602, and the port over which the service processor 602communicates. The first identifier 608 may or may not include anetwork-related unique identifier. The second identifiers 610 and 612may be the object instance numbers of the objects instantiated torepresent the hardware 604 and 606, respectively. For example, if theobject representing the hardware 604 is initiated first, it may have aninstance number of one, whereas if the object representing the hardware606 is instantiated second, it may have an instance number of two.

[0036]FIG. 7 shows diagrammatically an example object map 700 that isstored on a given service processor. The object map 700 includes entries702 a, 702 b, and 702 c. Each of these entries identifies an object witha first identifier indicating the service processor on which the objectis stored, which is the service processor storing the map 700, and asecond identifier distinguishing the object from other objects stored onthis service processor. For example, entries 702 a, 702 b, and 702 chave first identifiers 704 a, 704 b, and 704 c, respectively, thatidentify a service processor “A,” which is the service processor storingthe map 700. However, these entries have second identifiers 706 a, 706b, and 706 c, respectively, that identify different object instances“A-1,” “A-2,” and “A-3” that represent different hardware on the samenode as the service processor “A.” Each service processor thus maintainsan object map for the objects that are stored on the service processor.In this way, a global object map is distributed among all the serviceprocessors, where each service processor's own object map represents apart of the global object map.

[0037] Referring back to FIG. 5, self-discovery can specifically beperformed by each service processor broadcasting a message to all theother service processors over the service processor network (506). Thismessage includes the first identifier for its service processor, andalternatively also the second identifier for each object residing on theservice processor. That is, the message identifies all the objectsrepresenting hardware on the same node of which the service processor isa part. Each service processor can also receive the messages broadcastfrom the other service processors over the network (508). Each of thesemessages, too, includes the first identifier and alternatively also thesecond identifier for each object residing on the service processor fromwhich the message was received. Maintenance of the object map canspecifically be performed by each service processor storing the firstand the second identifiers for each object residing on itself in itsobject map (510).

[0038] The discovery process outlined in FIG. 5 is a broadcast-typeprocess, in which each service processor broadcasts a message to allother service processors. However, alternatively, the discovery processmay be a multicast-type process, in which the service processors aresegmented into two or more different groups. Each group may haveassociated therewith a specific multicast address. The serviceprocessors in a group broadcast their messages at this address, suchthat only the other processors in the group listen for these messages.In this way, each service processor sends a message only to the otherservice processor in the same group. The discovery process outlined inFIG. 5 can be considered a multicast-type process where the serviceprocessors to which the messages are sent are only those serviceprocessors within a single group of service processors.

[0039] Embodiments of the invention can also incorporate a pre-discoveryprocess not specifically outlined in FIG. 5. In pre-discovery, eachservice processor randomly generates a network address, such as anInternet Protocol (IP) address, within a given range, and sends alow-level message to the other devices on the network to ensure that theselected address has not already been taken by another device. If ithas, the device with the same address sends a message back to theservice processor, which generates another address and again sends amessage. This process is repeated until the service processor hasselected a unique network address.

Communication Between the Operating System and the Service Processors

[0040]FIG. 8 shows a method 800 of an embodiment by which communicationbetween an operating system (OS) and a cluster of service processors isaccomplished. The operating system is an example of a type of softwarecode. Other types of software code include firmware, for instance. Themethod 800 can be implemented in conjunction with the systems 100 and400 of FIGS. 1 and 4, respectively. The method 800 can also beimplemented in conjunction with an article of manufacture having acomputer-readable signal-bearing medium, such as a recordable datastorage medium, a modulated carrier signal, or another type of medium.

[0041] The OS communicates with the cluster of service processorsthrough a memory shared by all the service processors, such that the OSis preferably unaware which of the service processors performs a givenfunction. First, the OS stores a message in a part of the shared memoryallocated for a given type of messages (802). The service processor thathas responsibility for this part of the shared memory, such that it isresponsible for performing the functionality associated with the type ofmessages for which this part of the memory is allocated, processes themessage (804). The service processor may, for instance, send data storedin the message over the service processor network 204 to the console108. The service processor then stores a response in the part of theshared memory (806), so that the OS is aware that the message has beenproperly processed.

[0042]FIG. 9 shows diagrammatically an example system 900 in which theshared memory 104 has been divided into parts 104 a, 104 b, 104 c, 104d, and 104 e. The service processor 102 a is responsible for monitoringthe parts 104 a and 104 c for messages from the OS 106. That is, theservice processor 102 a is responsible for processing, or handling, themessages stored in the parts 104 a and 104 c by the OS 106. Similarly,the service processor 102 b is responsible for messages stored by the OS106 in the parts 104 b and 104 d, and the service processor 102 n isresponsible for messages stored by the OS 106 in the part 104 e. Theparts 104 a, 104 b, 104 c, 104 d, and 104 e into which the memory 104has been divided can be referred to as channels, such that each of theservice processors 102 a, 102 b, . . . , 102 n is responsible for aspecific subset of these channels at different points in time.

[0043] The messages stored in the different parts of the memory 104, andthus the channels into which the memory 104 has been divided, may be ofdifferent types. For example, a billboard type represents a genericmemory data structure in which data is stored in the channel. Aflow-controlled type represents a flow-controlled data structure inwhich the order of processing of the data is specified. Afirst-in-first-out (FIFO) type represents a FIFO-queuing data structurein which the first data stored is the first data processed. As a finalexample, an interrupt type represents a hardware feature which may bemanipulated according to instructions stored in a data structure, toalert a service processor that a given event has occurred, such as workhas arrived, such that particular actions may have to be performed.

[0044] Because each of the service processors 102 a, 102 b, . . . , 102n is responsible for a specific subset of the channels at differentpoints in time, it is said that the channels are dynamically allocatedamong the service processors. Dynamic allocation of the channels amongthe service processors in particular allows for failover and loadbalancing among the service processors. For example, if one channel isreceiving an inordinate amount of traffic, the other channels handled bythe same responsible service processor may be dynamically allocated toother service processors, for load-balancing purposes. As anotherexample, if a service processor fails, the channels for which it isresponsible may be dynamically allocated to other service processors,for failover purposes.

Communication Between the Console and the Service Processors

[0045]FIG. 10 shows a method 1000 of an embodiment by whichcommunication between a management console and a cluster of serviceprocessors is accomplished. The method 1000 can be implemented inconjunction with the systems 100 and 300 of FIGS. 1 and 3, respectively.The method 1000 can also be implemented in conjunction with an articleof manufacture having a computer-readable signal-bearing medium, such asa recordable data storage medium, a modulated carrier signal, or anothertype of medium.

[0046] The console communicates with the cluster of service processorsthrough any one of the service processors of a cluster, such that theconsole is preferably unaware that the service processors have beenclustered to perform functionality for the console. This serviceprocessor first receives a message from the console (1002), anddetermines whether the message is intended for itself or another serviceprocessor within the cluster (1004). For instance, the message mayrelate to hardware that is stored in the same node as the serviceprocessor, or in the same node as another service processor. As anotherexample, the message may relate to a function for which the serviceprocessor is responsible, or for which another service processor isresponsible.

[0047] If the message is intended for the service processor thatreceived the message, then this service processor processes the messageappropriately (1006), and sends a response back to the console (1008).However, if the message is intended for a different service processor,the service processor that received the message sends, or routes, themessage to this other service processor (1010), which itself processesthe message. The service processor that received the message thenreceives a response from this other service processor (1012), which itroutes back to the console (1014).

[0048] Other types of routing can also be accomplished of messages amongservice processors and the console, in addition to or in lieu of thatshown specifically shown in FIG. 10. For example, if the serviceprocessor that receives a request from the console is not the intendedservice processor, it may route the message to the intended serviceprocessor, which directly sends a reply back to the console instead ofrouting the reply back to the service processor that had received therequest. As another example, the console may send messages to specificservice processors that it believes is responsible for processing suchtypes of messages, which may be accomplished for performance,optimization, load balancing, and other purposes.

[0049] Furthermore, the console can become aware of a given objectrepresenting specific hardware on a specific service processor in anumber of different ways not limited by the invention itself. Theconsole may, for instance, ask for enumeration of the objects from theservice processor it knows. For example, one of the service processorsmay maintain what is referred to as a service processor type root classnode, which has the specific service processor instances as first-levelchildren nodes. The children nodes of these first-level children nodesare second-level children nodes maintained by the individual serviceprocessors themselves, which can be directly queried for the enumerationof the second-level children nodes. The second-level children nodes maycorrespond to, for instance, the objects representing the hardware on agiven service processor.

Advantages over the Prior Art

[0050] Embodiments of the invention allow for advantages over the priorart. The service processors of the nodes of a system aggregatethemselves in a cluster, such that the operating system (OS) and themanagement console do not have added overhead responsibilities. That is,the service processors are clustered without assistance from acontroller, host, master service processor, or other entity. This meansthat the OS and the console are not themselves required to performservice processor cluster management duties.

[0051] Because the OS places messages in different channels of memoryshared among all the service processors, the OS is preferably unawarewhich of the service processors actually handles a given type ofmessage. The OS thus does not have to track which service processorshandle which types of messages, and, significantly, does not have toconcern itself with load balancing and failover among the serviceprocessors. Similarly, the console communicates with the cluster ofservice processors through a given service processor, and thus ispreferably unaware that the cluster is performing functionality for theconsole. The console also does not have to track which serviceprocessors handle which types of messages, and does not have to concernitself with load balancing and failover.

[0052] In addition, embodiments of the invention can be performed withinthe firmware of the service processor, avoiding modification of the OSto ensure compatibility. This means that significant coding effort isavoided to implement the invention in such embodiments, because thedifferent types of operating systems that may be used do not have to bemodified in order to implement the invention, since the invention isimplemented in service processor firmware. Such service processorfirmware implementation also increases behavioral consistency of serviceprocessor functionality from OS to OS.

Generic Alternative Embodiment

[0053] Aspects of the invention are applicable in other contexts besidesan operating system (OS) communicating with a self-aggregated cluster ofservice processors through a shared memory. FIG. 11 shows a system 1100that is a generalization of the systems 100 and 400 of FIGS. 1 and 4,respectively. The entities 1102 a, 1102 b, . . . , 1102 n selfaggregateinto a cluster 1102. For example, the entities may be service processorsin the embodiment of the invention described in the previous sections ofthe detailed description. The host 1106 communicates with the cluster1102 through a shared memory 1104. For example, the host 1106 may be anOS in the embodiment of the invention described in the previous sectionsof the detailed description. Furthermore, the hardware that has beendescribed as that for which the service processors are responsible inthe embodiment described in the previous sections of the detaileddescription is one type of resource.

[0054] The shared memory 1104 is allocated into different parts, orchannels, one or more of which each of the entities 1102 a, 1102 b, . .. , 1102 n monitors for messages from the host 1106 for processing.Thus, communication between the host 1106 and the cluster 1102 can beaccomplished as has been more particularly described in conjunction withthe method 800 of FIG. 8, which is specific to the host 1106 being an OSand the entities 1102 a, 1102 b, . . . , 1102 n being serviceprocessors. Otherwise, however, the method 800 of FIG. 8 is applicableto the system 1100 as well.

[0055] As an example, the entities 1102 a, 1102 b, . . . , 1102 n may benetwork adapters each having a given bandwidth, and which canself-discover one another to form the cluster 1102. The bandwidthconstituting the resource on the network adapters. The host 1106 may bean OS that sends data over the cluster 1102 through the shared memory1104. In this way, the OS does not have to be reconfigured to supportmultiple network adapters, but rather treats the cluster 1102 as asingle, high-bandwidth network adapter. The adapters themselves handlefailover, load balancing, and connection routing among the networkadapters, such that the OS does not have to take on additional overheadfor such functionality.

[0056] As another example, clustering of mass storage controllers may beperformed, to allow a common queue of read/write/verify commands to beexecuted by any storage controller with access to the data. This isreferred to as self-aggregating RAID. The number and type of storagecontrollers can vary, as well as which of them handles a particularregion of clusters. The resources in this case are the storage devices,such as hard disk drives or other mass storage devices, managed by themass storage controllers. Furthermore, the controllers may, for example,dynamically enable extra redundancy by initiating mirroring tounallocated storage, which is known as RAID-1, or initiating stripingfor regions experiencing large reads/writes, which is known as RAID-0.Another example is a cluster of coprocessors, such as floating point,vector, graphics, or other types of processors, which can result in highresource utilization with low overhead.

Other Alternative Embodiments

[0057] It will be appreciated that, although specific embodiments of theinvention have been described herein for purposes of illustration,various modifications may be made without departing from the spirit andscope of the invention. For example, whereas four different types ofmessages that can be communicated between the operating system (OS) andthe cluster of service processors have been described, other types ofmessages can also be communicated between the OS and the cluster. Asanother example, the first identifier has been described as the Ethernetaddress of a service processor. However, other types and combinations ofidentifiers can also be used as the first identifier.

[0058] As another example, discovery of cluster peers can beaccomplished by multicasting rather than broadcasting. The role ascribedto the OS can also be performed by other software code executing on thehost, such as host firmware, a driver, a diagnostic program, and so on.Furthermore, the OS and/or the console may be aware of which serviceprocessor in the cluster is responsible for processing their requests,even though the invention has been substantially described as the OS andthe console being unaware of which service processor is so responsible.In addition, whereas the invention has been substantially described aspertaining to a shared memory, it is also applicable to other types ofshared resources, such as computer-readable media like hard disk drivesand other storage media. Accordingly, the scope of protection of thisinvention is limited only by the following claims and their equivalents.

We claim:
 1. A method comprising: self-discovering, at each of aplurality of entities of a system, all other of the entities toaggregate the entities as a cluster; and, maintaining, at each entitywithin the cluster, an object map representing resources of the systemfor which the entity is responsible as objects, each object uniquelyidentified by a first identifier corresponding to the entity on whichthe object resides and a second identifier to distinguish the objectfrom other of the objects also residing on the entity.
 2. The method ofclaim 1, wherein self-discovering, at each of the plurality of entitiesof the system, all other of the entities, comprises: sending a messageto all other of the entities, the message including the first identifierof the entity from which the message was sent; and, receiving a messagefrom each of all other of the entities, each message including the firstidentifier of the entity from which the message was received.
 3. Themethod of claim 1, further comprising communicating by a host with thecluster through a memory shared by all the entities, such that the hostneed not be aware which of the entities performs a given function. 4.The method of claim 3, wherein communicating by the host with thecluster comprises: storing a message by the host at a part of the sharedmemory; processing the message by one of the entities havingresponsibility for the part of the shared memory; and, storing aresponse by the one of the entities at the part of the shared memory. 5.The method of claim 1, wherein the first identifier comprises anidentifier unique to the entity, and the second identifier comprises atleast an object instance number.
 6. The method of claim 1, wherein theplurality of entities are one of a plurality of groups of entities ofthe system.
 7. The method of claim 1, wherein the entities are serviceprocessors, and the resources are hardware.
 8. The method of claim 1,wherein the entities are network adapters, and the resources arebandwidth.
 9. The method of claim 1, wherein the entities are massstorage controllers, and the resources are storage devices.
 10. A systemcomprising: a self-aggregated cluster of entities; and, a hostcommunicating with the cluster of entities through a memory shared byall the entities, such that the host need not be aware which of theentities performs a given function.
 11. The system of claim 10, whereinthe memory shared by all the entities is divided into channels, suchthat each of the entities is responsible for a subset of the channels.12. The system of claim 11, wherein the channels are dynamicallyallocated among the entities, such that the subset for which each of theentities is responsible may change over time.
 13. The system of claim10, wherein each entity monitors one a subset of the memory shared byall the entities to determine when the host has placed a message at anyof the one or more parts for handling by the entity.
 14. The system ofclaim 10, wherein the entities are service processors.
 15. The system ofclaim 10, wherein the entities are network adapters.
 16. The system ofclaim 10, wherein the entities are mass storage controllers.
 17. Anarticle comprising: a computer-readable medium; and, means in the mediumfor self-discovering at an entity of a system all other entities of thesystem to aggregate the entities as a cluster, for maintaining at theentity an object map representing resources of the system for which theentity is responsible as objects, and for communicating with a hostthrough a memory shared by all the entities.
 18. The article of claim17, wherein the entities are selected from the group of entitiescomprising: service processors, network adapters, and mass storagecontrollers.
 19. The article of claim 17, wherein the means is arecordable data storage medium.
 20. The article of claim 17, wherein themeans is a modulated carrier signal.